Evaluation of optimal size of illite adsorbent for 137Cs removal in contaminated artificial lake.

Since the Chernobyl and the Fukushima Daiichi disasters, contamination caused by radioactive accidents has attracted increasing attention. The present study evaluated immediate cleanup of 137Cs dissolved in surface water reservoir using an illite adsorbent, simulating an event of 137Cs contamination at Lake Paldang, South Korea. The study was conducted in two parts: (1) calculation of the residence time (tr) of illite adsorbent, and (2) evaluation of the adsorption time (ta) of illite adsorbent. tr was calculated based on physical properties (e.g., density, diameter, shape, and roughness) of the illite adsorbent at designated depth of surface water. Subsequently, ta was measured for 4 illite adsorbents (Korea01-Illite, Korea02-Illite, USA-Illite, and China-Illite) at 100 and 100,000 µg/L Cs, via kinetic adsorption experiment. Upon spraying of illite adsorbents with 50-150 µm diameter to locations where lake depth was between 6.5 m and 25.5 m, tr ranged from 0.132 to 3.300 h ta of 4 illite adsorbents was shorter than 0.6 and 2.5 h, for respective tests using 100 and 100,000 µg/L Cs. Based on the two characteristic times (tr and ta), the optimal particle diameter for the 4 illite adsorbents were evaluated at available lake depths in Lake Paldang. The study revealed that the USA-Illite is the efficient adsorbent at 100 µg/L Cs; in contrast, China-Illite could serve as the effective adsorbent at 100,000 µg/L Cs. Also, it was suggested that adsorbent efficiency had seasonal variations; tr was 2 h longer in winter than summer. In general, the study suggests that in the event of 137Cs contamination at Lake Paldang, Korea01-Illite is likely the best adsorbent to remove 137Cs due to its removal efficiency and accessibility from the illite deposit in Korea.

Gemcitabine therapy in patients with advanced pancreatic cancer.

BACKGROUND: Advanced, unresectable pancreatic cancer is an extremely aggressive disease. The 5-year survival rate for pancreatic cancer is only less than 5%. Current therapeutic options for patients with locally advanced or metastatic disease are limited. This analysis is a retrospective evaluation of the efficacy and toxicity of gemcitabine regimen as first-line chemotherapy in patients with advanced pancreatic cancer. METHODS: Seventeen chemotherapy-naive patients with advanced or recurred pancreatic cancer were consecutively treated. Gemcitabine was diluted in normal saline and administered intravenously over 1 hour. Gemcitabine 1,000 mg/m2 was administered once weekly for 3 out of every 4 weeks. RESULTS: The median age of patients was 55 years (range 44-82 years). Based on RECIST criteria, there were 5 cases of stable disease (45%) and 6 cases of progressive disease (55%) among the 11 assessable patients. The median survival time was 189 days (range, 84 to 409 days), the 1 year survival rate was 18% in all 17 patients. Grade 3-4 toxic side effect was leucopenia only (29%) and was easily managed without infection. CONCLUSION: Gemcitabine is well tolerated, but has no objective response in advanced pancreatic cancer.